const names = ["aaa", "bbb", "ccc", "zzz", NaN]

if(names.includes("aaa", 2)) {
  console.log("包含aaa");
} else {
  console.log("不包含aaa");
}
if(names.includes("aaa")) {
  console.log("包含aaa");
}
if(names.indexOf(NaN) !== -1) {
  console.log("indexof包含NaN");
}
if(names.includes(NaN)) {
  console.log("includes包含NaN");
}

